1. Field
The present application relates generally to touch screen devices, and more specifically to systems, methods, and devices for moisture detection and false touch rejection on touch screen devices.
2. Description of the Related Art
Moisture (e.g., sweat, spilled water, condensation, or any visible moisture) on a touch screen device can mimic the characteristics of an intended touch input generated by fingers, styluses, and/or other touch input mechanisms. As a result, moisture can cause false detections, inaccurate input recognitions, and/or errors, which can be problematic for a user. For example, a false detection due to moisture could cause a smartphone to prematurely send an incomplete email or text, or otherwise not perform as expected and/or as desired.
The issue behind this problem is that a touch screen device detects valid touches by processing changes in touch signals (e.g., electrical signals) on the touch screen. In some cases, moisture can cause a similar change to these touch signals as intended touch inputs.
There have been a number of previous attempts to address this issue. Some of these attempts have tried to use a threshold, where the touch screen device treats smaller touch signals below the threshold as false touches. The issue with this approach is that it will either not detect certain intended touch inputs that produce weaker signals, such as touches using a stylus, or will be slow to adapt to the presence of moisture and still have false detections.
Other attempts have looked at the persistence of changed signals to detect moisture or other unwanted matter on a touch screen. These attempts are slow to identify moisture and might recognize moisture after it is too late and false detections have already occurred.
Still other attempts have looked at clusters of values to see if the clusters fall below some threshold. These techniques do not account for the erratic behavior of touch signal changes due to moisture, and that the presence of moisture can cause spikes in touch signals above the threshold.
Accordingly, because of the shortcomings of the previous attempts, there is a need for more effective systems and methods for detecting the presence of moisture on touch screens of touch screen devices and for rejecting false detections due to the presence of moisture.